3-Bromophenylglyoxal Hydrate: Properties, Handling & Lab Use

3-Bromophenylglyoxal hydrate is an aryl alpha-ketoaldehyde reagent bearing a meta-bromo substituent, widely employed as a reactive electrophilic building block in heterocyclic synthesis, condensation reactions, and bioconjugation chemistry.

Chemical Name

3-Bromophenylglyoxal hydrate

CAS Number

Needs review — not confirmed in source material

Molecular Formula (hydrate)

C8H7BrO3 (as monohydrate; verify)

Functional Groups

Aromatic ketone, aldehyde (as geminal diol in hydrate form), aryl bromide

Key Reactivity

Electrophilic alpha-ketoaldehyde; undergoes condensation with amines, hydrazines, and 1,2-bifunctional nucleophiles

SKU

D691516

Recommended Storage

Cool, dry, dark conditions; refrigeration recommended (2–8 °C); verify with SDS

Chemical Identity and Structure

3-Bromophenylglyoxal hydrate is an aryl glyoxal compound in which a glyoxal moiety (–CO–CHO) is attached to a benzene ring carrying a bromine atom at the meta (3-) position. In the solid state and in aqueous solution, the aldehyde carbonyl typically exists as a geminal diol (hydrate), rendering the compound more stable and easier to handle than the anhydrous free aldehyde.

The molecule combines two distinct reactive sites: (1) the alpha-ketoaldehyde system, which is a potent electrophile, and (2) the aryl bromide, which is available for palladium-catalyzed cross-coupling reactions (e.g., Suzuki, Heck, Sonogashira). This dual functionality makes 3-Bromophenylglyoxal hydrate a versatile bifunctional building block for multi-step synthetic sequences.

Note: Exact molecular weight, CAS number, and purity specification should be confirmed against the current product datasheet (SKU D691516) and Certificate of Analysis.

Handling, Storage and Safety

Personal Protective Equipment (PPE): Handle 3-Bromophenylglyoxal hydrate wearing appropriate nitrile gloves, a laboratory coat, and safety glasses. Where fine powder or dust may be generated, use a suitable dust mask or fume hood to avoid inhalation.

Storage: Store in a tightly sealed container under cool (recommended 2–8 °C), dry, and dark conditions to prevent hydrolysis, oxidation, or moisture uptake beyond the hydrate stoichiometry. Prolonged exposure to air, light, or elevated temperatures may lead to decomposition or discoloration. Always reseal after use.

Stability: As an alpha-ketoaldehyde derivative, the compound may be sensitive to strong bases and oxidizing agents. Confirm compatibility before use with specific reaction conditions.

Disposal: Dispose of waste according to local institutional and governmental regulations for halogenated organic compounds. Consult the Safety Data Sheet (SDS) for full hazard classifications and first-aid measures before working with this material.

Review flag: Full GHS hazard classifications and H/P statements are not available in the provided source material; refer to the official SDS for SKU D691516.

Synthetic Applications and Research Uses

Heterocyclic Synthesis: Arylglyoxal hydrates are classical precursors in the synthesis of nitrogen-containing heterocycles. 3-Bromophenylglyoxal hydrate can react with 1,2-diamines (e.g., o-phenylenediamine) to afford quinoxalines, or with amidines and guanidines to yield imidazoles and related systems. The meta-bromo substituent on the aryl ring provides a handle for further functionalization via cross-coupling after ring formation.

Cross-Coupling Chemistry: The aryl bromide moiety is well-suited to palladium-catalyzed Suzuki–Miyaura, Heck, Sonogashira, and Buchwald–Hartwig reactions, enabling introduction of diverse aryl, vinyl, alkynyl, or amino groups in subsequent steps. This makes the compound particularly valuable as an intermediate for library synthesis or medicinal chemistry campaigns.

Bioconjugation and Arginine Modification: Alpha-ketoaldehydes are known to react selectively with the guanidinium side chain of arginine residues under mildly acidic conditions, forming stable adducts. Phenylglyoxal derivatives have been used as arginine-selective protein modification reagents in biochemical studies.

Condensation and Multicomponent Reactions: The reactive dicarbonyl system participates in Hantzsch, Biginelli, and other multicomponent condensations, providing rapid access to complex scaffolds from simple starting materials.

Review flag: Specific literature references, yields, and reaction conditions for 3-Bromophenylglyoxal hydrate specifically are not provided in the source material and should be verified against primary literature.

Preparation and Solution Handling Tips

Solubility: Arylglyoxal hydrates are generally soluble in polar organic solvents such as DMSO, DMF, methanol, ethanol, and acetonitrile, and show moderate solubility in water. Solubility in non-polar solvents is typically low. Verify solubility for your specific application; the hydrate form may require brief warming to dissolve fully.

Stock Solutions: Prepare stock solutions in anhydrous DMSO or DMF under inert atmosphere where long-term stability is required. Aliquot and store at –20 °C to minimize repeated freeze-thaw cycles and degradation.

Weighing: Tare the balance and weigh quickly to minimize atmospheric moisture uptake. Use a covered weighing boat and transfer immediately to a sealed vial. For hygroscopic or air-sensitive handling, use a glove bag or glove box.

Reaction Setup: When using as an electrophilic partner in condensations, ensure the reaction medium is compatible with the hydrate form; some protocols may require azeotropic removal of water or use of a Dean–Stark trap to drive equilibrium toward the free aldehyde.

Review flag: Specific solubility data and recommended stock concentrations for D691516 are not confirmed in the source material; consult the product datasheet.

Quality, Purity and Regulatory Notes

Purity: Research-grade 3-Bromophenylglyoxal hydrate (SKU D691516) is supplied by Aladdin Scientific for laboratory research use. Purity specification should be confirmed on the current Certificate of Analysis (CoA) available at the time of purchase. Typical analytical methods for arylglyoxal hydrates include HPLC, NMR (confirming hydrate geminal diol structure), and elemental analysis.

Intended Use: This product is intended for research purposes only and is not approved for use in diagnostic, therapeutic, food, drug, or cosmetic applications unless explicitly stated.

Lot-to-Lot Variability: Always reference the lot-specific CoA for confirmed purity, melting point, and spectral data before initiating sensitive synthetic or biological assays.

Export and Regulatory Compliance: Halogenated organic compounds may be subject to export control regulations in certain jurisdictions. Procurement and lab managers should verify applicable local regulations prior to ordering and importation.

Review flag: Exact purity percentage, melting point, and analytical specification for D691516 are not provided in the source material; flag for confirmation against the official CoA.

Frequently asked questions

What is the difference between 3-Bromophenylglyoxal hydrate and the anhydrous form?

The hydrate form contains water molecules associated with the aldehyde carbonyl, converting it to a geminal diol (R–CH(OH)2). This makes the compound more stable and easier to weigh and handle compared to the free anhydrous aldehyde. In most synthetic reactions, the hydrate liberates the active free aldehyde in situ under the reaction conditions. Account for the additional molecular weight of water when calculating molar equivalents.

Can 3-Bromophenylglyoxal hydrate be used in palladium-catalyzed cross-coupling reactions?

Yes. The aryl bromide functionality in 3-Bromophenylglyoxal hydrate is amenable to standard palladium-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Heck, Sonogashira, and Buchwald–Hartwig couplings. Care should be taken to ensure that the reaction conditions (base, temperature, solvent) are compatible with the sensitive alpha-ketoaldehyde functionality, or that cross-coupling is performed on a derivative after the glyoxal moiety has been elaborated or protected.

How should I calculate the molar amount when weighing 3-Bromophenylglyoxal hydrate?

Use the molecular weight of the hydrate form (not the anhydrous glyoxal) as stated on the product label and Certificate of Analysis. Divide the mass weighed (in grams) by the molecular weight (in g/mol) to obtain moles. If the hydration state is uncertain (e.g., monohydrate vs. dihydrate), confirm the exact formula and MW from the CoA for SKU D691516 before proceeding.

Is 3-Bromophenylglyoxal hydrate suitable for arginine modification in proteins?

Phenylglyoxal derivatives are well-established arginine-selective protein modification reagents; the alpha-ketoaldehyde reacts selectively with the guanidinium group of arginine under mildly acidic aqueous conditions. The meta-bromo substituent may influence reactivity and selectivity compared to unsubstituted phenylglyoxal. Researchers should validate conditions specific to their protein target and confirm reagent compatibility with their buffer system. Specific data for 3-Bromophenylglyoxal hydrate in bioconjugation are not available in the current source material.

What solvents are recommended for dissolving 3-Bromophenylglyoxal hydrate?

Arylglyoxal hydrates are generally soluble in polar organic solvents such as DMSO, DMF, methanol, ethanol, and acetonitrile. DMSO is commonly preferred for preparing stock solutions due to its excellent solvating power and compatibility with most biological and synthetic assays. Solubility in purely non-polar solvents is expected to be low. Always verify solubility empirically for your specific application and consult the D691516 datasheet for confirmed solubility data.

References

1. Takahashi K. Reaction of phenylglyoxal with arginine residues in proteins. J Biol Chem. (General reference for arylglyoxal arginine modification — specific volume, page and year not confirmed from source material.)
2. March J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. Wiley-Interscience. (General reference for alpha-ketoaldehyde and heterocycle-forming condensation reactions.)
3. Aladdin Scientific. Product Datasheet and Certificate of Analysis for 3-Bromophenylglyoxal hydrate, SKU D691516. (Primary source for confirmed purity, MW, CAS, and storage specifications.)

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.